Redeeming bootleg code, download still costs a penny?

Topic. I applied a membership download code to a bootleg download order, and it only covers $9.99 of the $10 download cost. Is this a glitch or just a troll? Do i really have to enter my credit card info to cover one cent? It's more than an issue of principle (though there is a matter of principle); i've had similarly small charges red flagged and/or declined by my credit card company, as they look suspicious.